DP Chemistry (last assessment 2024)

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Question 23M.2.SL.TZ2.a

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Date May 2023 Marks available [Maximum mark: 2] Reference code 23M.2.SL.TZ2.a
Level SL Paper 2 Time zone TZ2
Command term Calculate Question number a Adapted from N/A
a.
[Maximum mark: 2]
23M.2.SL.TZ2.a

The concentration of methanoic acid was found by titration with a 0.200 mol dm−3 standard solution of sodium hydroxide, NaOH (aq), using an indicator to determine the end point.

Calculate the pH of the sodium hydroxide solution.

[2]

Markscheme

«[OH−] = 0.200 mol dm−3»

ALTERNATIVE 1:
«pOH = −log10(0.200) =» 0.699 ✓
«pH = 14.000 − 0.699 =» 13.301 ✓

ALTERNATIVE 2:
«[H+] = 1.00x10-140.200 = » 5.00 × 10−14 «mol dm−3» ✓
«pH = −log10(5.00 × 10−14)» = 13.301 ✓

 

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